JP6035097B2 - Condensation reaction product solution for trench filling, and method for producing trench filling film - Google Patents

Description

  The present invention relates to a condensation reaction solution and a method for manufacturing a trench buried film for an insulating protective film in a trench formed in a semiconductor element, that is, for trench filling.

  A shallow trench isolation technique (STI technique) has been developed as one technique for electrically isolating circuit elements such as transistors, which are components of electronic devices such as semiconductor devices. The STI technique is a technique for electrically separating circuit elements by forming a trench in a gap between circuit elements in a substrate and embedding an insulating material in the trench.

  As a material used for such trench filling, silicon oxide is widely used because high electrical insulation is required.

  In order to embed a silicon oxide film in the trench, a silicon oxide film is conventionally formed on a silicon substrate having a trench by a sputtering method typified by a high-density plasma CVD method.

  As a method other than the sputtering method, a method of forming a silica film by firing after embedding fine grooves of a trench by a coating method is known. For example, a silanol compound (see, for example, Patent Document 1), polysilazane (for example, Patent Document 2). Etc.) are used.

JP-A-2004-363615 JP-A-11-307626

  However, with the recent miniaturization of semiconductor elements, the trench opening width tends to be small and the aspect ratio tends to be large, the trench width is 0.2 μm or less, and the aspect ratio (the trench depth is divided by the trench opening width). If a silicon oxide film is buried in a fine groove having a value of 2 or more by the CVD method, there is a problem that voids are easily generated in the fine groove.

  In addition, when a coating method is used, if a silanol compound or polysilazane is used as a precursor, thermal shrinkage of the material occurs in the process of conversion from the precursor to silicon oxide, and voids are generated in the embedded portion and peeling from the substrate. There is a problem of the occurrence of.

  The present invention has been made in view of the above circumstances, and the problem is that when a silicon oxide is embedded in a trench having a fine line width formed on a substrate by a coating method, the coating film is fired to form a trench. The object of the present invention is to provide a trench filling condensation reaction solution capable of suppressing the generation of voids in the trench when forming the buried film, and a method for producing the trench buried film.

  As a result of intensive studies to solve the above problems, the present inventors have found the following condensation reaction product solution for trench filling and a method for producing a trench filling film, and have completed the present invention. That is, the present invention is as follows.

[1] A trench filling condensation product solution comprising a condensation reaction product of a polysiloxane compound and silica particles, and an organic solvent,
The polysiloxane compound has the following general formula (1):
R _n SiX ¹ _4-n (1)
{In the formula, n is an integer of 0 to 4, R is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and X ¹ is a halogen atom, an alkoxy group having 1 to 6 carbon atoms or an acetoxy group. The plurality of X ¹ may be the same or different. }
Derived from the silane compound represented by
The organic solvent has an organic solvent (A) having a boiling point of less than 130 ° C. of 50% by mass to 99% by mass and an organic solvent having a boiling point of 130 ° C. or higher (B) with respect to 100% by mass of the total amount of the organic solvent. ) Containing 1% by mass to 50% by mass of a trench filling condensation reaction product solution.
[2] The polysiloxane compound has the following general formula (2):
SiX ² ₄ (2)
{Wherein X ² represents a halogen atom, an alkoxy group having 1 to 6 carbon atoms or an acetoxy group, and a plurality of X ² may be the same or different. }
The condensation reaction product solution for trench embedding according to the above [1], which is derived from a tetrafunctional silane compound represented by:
[3] The trench according to [1] or [2], wherein the organic solvent (A) is at least one selected from the group consisting of alcohol, polyhydric alcohol derivative, ketone, ester, ether, and hydrocarbon. Condensation reaction product solution for embedding.
[4] In any one of the above [1] to [3], the organic solvent (B) is at least one selected from the group consisting of alcohol, polyhydric alcohol derivative, ketone, ester, ether, and hydrocarbon. The condensation reaction product solution for trench filling as described.
[5] A step of applying the trench filling condensation reaction product solution according to any one of [1] to [4] to a substrate having a trench by a spin coating method;
And a step of firing the substrate coated with the condensation reaction product solution.

  According to the present invention, when a silicon oxide is buried in a trench having a fine line width formed on a substrate by a coating method, a condensation reaction for filling a trench can suppress the generation of voids in the trench when the coating film is baked. It is possible to provide a manufacturing method of a physical solution and a trench buried film.

  Hereinafter, modes for carrying out the present invention (hereinafter abbreviated as “embodiments”) will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary.

<Condensation reaction solution for trench filling>
One aspect of the present invention is a condensation reaction solution for trench filling, which includes a condensation reaction product of a polysiloxane compound and silica particles (also referred to simply as a condensation reaction product in the present disclosure) and an organic solvent,
The polysiloxane compound has the following general formula (1):
R _n SiX ¹ _4-n (1)
{In the formula, n is an integer of 0 to 4, R is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and X ¹ is a halogen atom, an alkoxy group having 1 to 6 carbon atoms or an acetoxy group. The plurality of X ¹ may be the same or different. }
The organic solvent has a boiling point of 50% by mass or more and 99% by mass or less, and a boiling point of the organic solvent (A) having a boiling point of less than 130 ° C. with respect to 100% by mass of the total amount of the organic solvent. A condensation reaction product solution for filling a trench is provided that contains 1% by mass or more and 50% by mass or less of an organic solvent (B) having a temperature of 130 ° C. or higher.

  As described above, the present invention provides a trench having a fine line width by mixing a condensation reaction product of a polysiloxane compound and silica particles and two or more kinds of organic solvents having different boiling points and having an optimized ratio. It becomes possible to bury silicon oxide while suppressing the generation of voids in the trench.

  In the present disclosure, the condensation reaction product of a polysiloxane compound and silica particles refers to a condensation component (in the present disclosure) containing a polysiloxane compound derived from the silane compound represented by the general formula (1) and silica particles. , Which may be simply referred to as a condensation component) means a product obtained by a condensation reaction. Accordingly, the condensation reaction product of the polysiloxane compound and the silica particles is derived from the product derived only from the structure derived from the polysiloxane compound and the structure derived from the silica particles, and the structure derived from the polysiloxane compound, the silica particles. Both structures and products having structures derived from additional components optionally included in the condensation component are included.

(Polysiloxane compound)
The polysiloxane compound used in the present invention is derived from the silane compound represented by the general formula (1). More specifically, the polysiloxane compound is a polycondensate of a silane compound represented by the general formula (1). As the silane compound represented by the general formula (1), one or more compounds can be used.

  Specific examples of R in the general formula (1) include: methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, t-butyl, n-pentyl, iso-pentyl, neopentyl, cyclopentyl, n -Acyclic such as hexyl, iso-hexyl, cyclohexyl, n-heptyl, iso-heptyl, n-octyl, iso-octyl, t-octyl, n-nonyl, iso-nonyl, n-decyl, iso-decyl or the like A cyclic aliphatic hydrocarbon group; acyclic and cyclic alkenyl such as vinyl, propenyl, butenyl, pentenyl, hexenyl, cyclohexenyl, cyclohexenylethyl, norbornenylethyl, heptenyl, octenyl, nonenyl, decenyl, styryl Group: benzyl, phenethyl, 2-methylbenzyl, 3-methylben Le, aralkyl groups such as 4-methylbenzyl; PhCH = CH- Araarukeniru group such group; and the like are; phenyl, tolyl, xylyl, or similar aryl groups. Further, specific examples of R include a hydrogen atom. Among these, R is preferably a hydrogen atom, a methyl group or an ethyl group in that a condensation reaction product having a small weight loss and a small shrinkage rate can be provided upon conversion to silicon oxide during firing. More preferably, it is a methyl group.

Specific examples of X ^{1 in} the general formula (1) include, for example: halogen atoms such as chlorine, bromine and iodine; methoxy group, ethoxy group, n-propyloxy group, iso-propyloxy group, n-butyloxy group , T-butyloxy group, n-hexyloxy group, cyclohexyloxy group and other alkoxy groups; acetoxy group; and the like. Among these, a chlorine atom, a bromine atom, an iodine atom, a methoxy group, an ethoxy group, and an acetoxy group are preferable from the viewpoint of high reactivity of the condensation reaction.

Furthermore, the polysiloxane compound is a compound represented by the following general formula (2) from the viewpoint of giving a condensation reaction product having high adhesion to the substrate.
SiX ² ₄ (2)
{Wherein X ² represents a halogen atom, an alkoxy group having 1 to 6 carbon atoms or an acetoxy group, and a plurality of X ² may be the same or different. }
It is preferably derived from a silane compound containing a tetrafunctional silane compound represented by: More preferably, the polysiloxane compound is derived from a tetrafunctional silane compound represented by the general formula (2).

Specific examples of X ^{2 in} the general formula (2) include: halogen atoms such as chlorine, bromine and iodine; methoxy group, ethoxy group, n-propyloxy group, iso-propyloxy group, n-butyloxy group , T-butyloxy group, n-hexyloxy group, alkoxy group such as cyclohexyloxy group; acetoxy group and the like. Among these, a chlorine atom, a bromine atom, an iodine atom, a methoxy group, an ethoxy group, and an acetoxy group are preferable from the viewpoint of high reactivity of the condensation reaction.

(Manufacture of polysiloxane compounds)
The polysiloxane compound can be produced by a method of polycondensing the above-described silane compound in the presence of water, for example. At this time, it is preferably 0.1 equivalents or more and 10 equivalents or less, more preferably 0.4 equivalents or more, based on the number of X ¹ contained in the silane compound represented by the general formula (1) in an acidic atmosphere. Polycondensation is carried out in the presence of water in the range of 8 equivalents or less. When the amount of water is within the above range, it is preferable because the pot life of the condensation reaction product solution can be lengthened and the crack resistance after film formation can be improved.

When the silane compound used for producing the polysiloxane compound is a compound containing a halogen atom or an acetoxy group as X ¹ in the general formula (1), the reaction is performed by adding water for the condensation reaction. Since the system is acidic, it does not matter whether or not an acid catalyst is used in addition to the silane compound. On the other hand, when X ¹ in the general formula (1) is an alkoxy group, it is preferable to add an acid catalyst.

  Examples of the acid catalyst include inorganic acids and organic acids. Examples of the inorganic acid include hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid, phosphoric acid, and boric acid. Examples of the organic acid include acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, oxalic acid, maleic acid, methylmalonic acid, benzoic acid, and p-aminobenzoic acid. Examples include acid, p-toluenesulfonic acid, benzenesulfonic acid, trifluoroacetic acid, formic acid, malonic acid, sulfonic acid, phthalic acid, fumaric acid, citric acid, tartaric acid, citraconic acid, malic acid, glutaric acid and the like.

  Said inorganic acid and organic acid can each be used 1 type or in mixture of 2 or more types. The amount of the acid catalyst used is an amount that adjusts the pH of the reaction system when producing the polysiloxane compound to a range of 0.01 to 7.0, preferably 5.0 to 7.0. preferable. In this case, the weight average molecular weight of the polysiloxane compound can be controlled well.

  The polysiloxane compound can be produced in an organic solvent or a mixed solvent of water and an organic solvent. Examples of the organic solvent include alcohols, esters, ketones, ethers, aliphatic hydrocarbon compounds, aromatic hydrocarbon compounds, amide compounds, and the like.

  Examples of the alcohols include: monohydric alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, and butyl alcohol; polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, glycerin, trimethylolpropane, and hexanetriol; ethylene glycol monomethyl Ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene Glycol monopropyl ether, mono ethers of polyhydric alcohols such as propylene glycol monobutyl ether; and the like.

  Examples of the esters include methyl acetate, ethyl acetate, butyl acetate and the like. Examples of the ketones include acetone, methyl ethyl ketone, and methyl isoamyl ketone.

  As the ethers, in addition to the monoethers of the above polyhydric alcohols, for example: ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol dibutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, Polyhydric alcohol ethers obtained by alkyl etherifying all hydroxyl groups of polyhydric alcohols such as propylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, and diethylene glycol diethyl ether; tetrahydrofuran, 1,4-dioxane, anisole and the like.

  Examples of the aliphatic hydrocarbon compounds include hexane, heptane, octane, nonane and decane.

  Examples of the aromatic hydrocarbon compounds include benzene, toluene, xylene and the like.

  Examples of the amide compounds include dimethylformamide, dimethylacetamide, N-methylpyrrolidone and the like.

  Among these solvents, methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and dimethylformamide, dimethylacetamide, and N-methylpyrrolidone is preferable because it can be easily mixed with water and can easily disperse silica particles.

  In a preferred embodiment, the polysiloxane compound can be produced by hydrolytic condensation in an aqueous alcohol solution under weakly acidic conditions of pH 5 or more and less than 7.

These solvents may be used alone or in combination of a plurality of solvents. Moreover, you may react in a bulk, without using the said solvent.

  The reaction temperature for producing the polysiloxane compound is not particularly limited, but it is preferably -50 ° C or higher and 200 ° C or lower, more preferably 0 ° C or higher and 150 ° C or lower. By performing the reaction in the above temperature range, the molecular weight of the polysiloxane compound can be easily controlled.

The content of the polysiloxane compound in the total amount of the condensation component of 100% by mass is preferably 40% by mass or more and 99% by mass or less in terms of the condensation conversion amount of the polysiloxane compound. However, in the present disclosure, the total amount of the condensation component is determined using values obtained by replacing the amount of the polysiloxane compound and the amount of the silane compound (if present) with the respective equivalent amounts of condensation. The condensation conversion amount of the polysiloxane compound and the condensation conversion amount of the silane compound are the condensation reactive groups (specifically, X ¹ in the general formula (1)) present in the polysiloxane compound and the silane compound, respectively. , Means the amount obtained by substituting with 1/2 oxygen atom. The content of the polysiloxane compound as the condensation conversion amount is preferably 40% by mass or more from the viewpoint of good film formability. The content is more preferably 50% by mass or more, and still more preferably 55% by mass or more. On the other hand, it is preferable that the content is 99% by mass or less from the viewpoint of obtaining a trench filling film which gives a low shrinkage rate and good crack resistance. The content is more preferably 90% by mass or less, and still more preferably 85% by mass or less.

(Silica particles)
Examples of the silica particles used in the present invention include fumed silica and colloidal silica.

  The fumed silica can be obtained by reacting a compound containing a silicon atom with oxygen and hydrogen in a gas phase. Examples of the silicon compound used as a raw material include silicon halide (for example, silicon chloride).

  The colloidal silica can be synthesized by a sol-gel method in which a raw material compound is hydrolyzed and condensed. Examples of the raw material compound for colloidal silica include alkoxy silicon (for example, tetraethoxysilane) and halogenated silane compounds (for example, diphenyldichlorosilane). Especially, since it is preferable that there are few impurities, such as a metal and a halogen, the colloidal silica obtained from the alkoxy silicon is more preferable.

  The average primary particle diameter of the silica particles is preferably 1 nm or more and 120 nm or less, more preferably 40 nm or less, still more preferably 20 nm or less, and most preferably 15 nm or less. When the average primary particle diameter is 1 nm or more, crack resistance is good, and when it is 120 nm or less, trench embedding is good and preferable.

  The average secondary particle diameter of the silica particles is preferably 2 nm or more and 250 nm or less, more preferably 80 nm or less, still more preferably 40 nm or less, and most preferably 30 nm or less. When the average secondary particle diameter is 2 nm or more, the crack resistance is good, and when the average secondary particle diameter is 250 nm or less, the trench embedding property is good.

  In addition, the average secondary particle diameter of the silica particles is within the above range and 0.1 to 3 times the minimum opening width among the trenches formed in the substrate, the embedding property in the trenches is It is preferable in terms of goodness, and more preferably 0.1 to 2 times the minimum opening width.

  The average primary particle diameter is a value obtained by calculation from the specific surface area of BET, and the average secondary particle diameter is a value measured with a dynamic light scattering photometer.

  The shape of the silica particles can be spherical, rod-shaped, plate-shaped, fibrous, or a shape in which two or more of these are combined, but is preferably spherical. In addition, the spherical shape here means a substantially spherical shape including a spheroid, an oval and the like in addition to a true spherical shape.

The specific surface area of the silica particles is preferably a BET specific surface area of 25 m ² / g or more, more preferably 70 m ² / g or more, in view of good chemical resistance such as HF resistance of the coating film. Preferably it is 140 m < ² > / g or more, Most preferably, it is 180 m < ² > / g or more. The BET specific surface area is a value measured by a method calculated from the pressure of N2 molecules and the gas adsorption amount.

  The silica particles are not limited as long as they meet the above requirements, and commercially available products can also be used. Commercially available products include colloidal silica such as LEVASIL series (manufactured by HC Starck Co., Ltd.), methanol silica sol, IPA-ST, MEK-ST, NBA-ST, XBA-ST, DMAC-ST, ST-UP. , ST-OUP, ST-20, ST-40, ST-C, ST-N, ST-O, ST-50, ST-OL (manufactured by Nissan Chemical Industries, Ltd.), Quatlon PL series (Fuso Chemical Co., Ltd.), OSCAL series (Catalyst Kasei Kogyo Co., Ltd.), etc .; As powdered silica particles, for example, Aerosil 130, 300, 380, TT600, OX50 (above, Nippon Aerosil Co., Ltd.) ), Sildex H31, H32, H51, H52, H121, H122 (above, manufactured by Asahi Glass Co., Ltd.), E220A, E2 0 (manufactured by Nippon Silica Industrial (Ltd.)), SYLYSIA470 (manufactured by Fuji Silysia Chemical (Co., Ltd.)), SG Flake (manufactured by Nippon Sheet Glass Co., Ltd.), and the like, respectively. Silica particles can also be used in a form dispersed in a dispersion medium. The silica particle content in that case is calculated using a value obtained by multiplying the mass of the net silica particles, that is, the mass of the dispersion, by the concentration of the silica particles.

  The content of the silica particles in the total amount of the condensation component of 100% by mass is 1% by mass to 60% by mass. The content of 1% by mass or more is preferable in that a low shrinkage rate and good crack resistance can be obtained. The content is more preferably 10% by mass or more, and still more preferably 15% by mass or more. On the other hand, the content is preferably 60% by mass or less from the viewpoint of good film formability. The content is more preferably 50% by mass or less, and still more preferably 45% by mass or less.

(Silane compound)
The condensation component used in the production of the condensation reaction product used in the present invention can be composed of the above polysiloxane compound and silica particles, or can contain additional components. As an additional component, the silane compound represented, for example by the said General formula (1) can be used. When such a silane compound is used as an additional component, the pot life of the condensation reaction product solution is particularly good and preferable. When the silane compound represented by the general formula (1) is used as an additional component, for example, the following two-stage condensation reaction can be employed. That is, a polysiloxane compound and silica particles are first subjected to a condensation reaction by a method of adding a polysiloxane compound solution to a dispersion in which silica particles are dispersed in a solvent to cause a condensation reaction (first step). Next, the silane compound represented by the general formula (1) is further reacted with the obtained reaction solution (second stage). The silane compound represented by the general formula (1) used as the condensation component may be one kind or plural kinds. When using a plurality of types of silane compounds, for example, in the second stage, they may be added to the reaction system one by one sequentially, or after mixing a plurality of types of silane compounds into the reaction system. Also good.

When the silane compound represented by the general formula (1) is used as the condensation component, the content of the silane compound in the total amount of the condensation component of 100% by mass exceeds 0% by mass in terms of the condensation conversion amount of the silane compound. It is preferable to set so that it is below mass%. The condensation conversion amount of the silane compound means an amount obtained by substituting X ¹ in the general formula (1) with ½ oxygen atoms as described above. It is preferable that the content exceeds 0% by mass because the pot life of the condensation reaction product solution is long. The content is more preferably 0.01% by mass or more, and still more preferably 0.03% by mass or more. On the other hand, it is preferable that the content is 40% by mass or less in terms of good crack resistance. The content is more preferably 30% by mass or less, and still more preferably 20% by mass or less.

  The weight average molecular weight of the condensation reaction product is preferably 1,000 or more and 20,000 or less, and more preferably 1,000 or more and 10,000 or less. When the condensation reaction product has a weight average molecular weight of 1,000 or more, the film formability and crack resistance are good, and when the weight average molecular weight is 20,000 or less, the pot life of the condensation reaction product solution is preferably long. . The weight average molecular weight is a value calculated using gel permeation chromatography and calculated in terms of standard polymethyl methacrylate. The molecular weight can be measured, for example, using a gel permeation chromatography (GPC), HLC-8220, TSKgelGMHRHR-M column manufactured by Tosoh Corporation, and the condensation reaction product can be measured as a 1% by mass solution in acetone solvent. The weight average molecular weight (Mw) in terms of standard polymethyl methacrylate can be determined by the total (RI).

  The formation of the condensation reaction product can be confirmed using, for example, a nuclear magnetic resonance apparatus (NMR). For example, using a nuclear magnetic resonance apparatus: ECA700 and probe SI10, confirmation is made by measuring a sample obtained by adding 0.9 parts by mass of chrominium acetylacetonate to 100 parts by mass of a heavy acetone solution having a condensation reaction product concentration of 25% by mass. it can.

(solvent)
The condensation reaction product solution of the present invention contains an organic solvent. In the present invention, two or more kinds of solvents having different boiling points are mixed in order to solve the problem. In the method of forming a silica film by firing after embedding fine trenches by a coating method, the generation of voids in the buried portion is caused by thermal contraction of the material. The reason why the voids are caused by heat shrinkage is that the fluidity of molecules in the coating film is reduced during heating. In the present invention, two or more kinds of organic solvents having different boiling points are mixed and the solvent is volatilized stepwise from the coating film, thereby ensuring the fluidity of molecules in the coating film and preventing voids from occurring even when heat shrinkage occurs. It was found that no trench was formed and the trench filling property was good.

  Furthermore, it has been found that a particularly remarkable effect can be obtained by controlling the volatilization amount of the solvent during coating and the volatilization amount of the solvent during preliminary curing in the coating method. In the coating method, a coating film is formed by coating a coating solution on a substrate and volatilizing a solvent to some extent. Further, preliminary curing by heating is performed to volatilize the solvent. The pre-cured coating film (also referred to as a pre-cured film in the present disclosure) is in a solid state, and the fluidity of molecules in the pre-cured film is greatly reduced. Therefore, the volatilization of the solvent at the time of application and the volatilization of the solvent at the time of preliminary curing have a great influence on the trench filling property.

  From this point of view, in the present embodiment, the organic solvent has a structure in which the organic solvent (A) having a boiling point of less than 130 ° C. has a boiling point of 50% by mass to 99% by mass with respect to 100% by mass of the total solvent. Is a mixed solvent in which the organic solvent (B) having a temperature of 130 ° C. or higher is 1% by mass or more and 50% by mass or less with respect to 100% by mass of the total solvent amount. The organic solvent is preferably an organic solvent (B) having a boiling point of less than 130 ° C. and an organic solvent (B) having a boiling point of 130 ° C. or more and a boiling point of 130 ° C. or more with respect to the total amount of the solvent. It is a mixed solvent which is 10 mass% or more and 40 mass% or less with respect to the quantity. When the organic solvent (A) in the mixed solvent is 50% by mass or more with respect to the total amount of the solvent, the film formability of the coating film is improved, and when it is 99% by mass or less, the trench embedding property is improved. . Similarly, when the organic solvent (B) having a boiling point of 130 ° C. or higher is 1% by mass or more with respect to the total amount of the solvent, the trench embedding property is improved, and when the organic solvent (B) is 50% by mass or less, the coating film is formed. Will be better.

  Each of the organic solvent (A) and the organic solvent (B) may be a single solvent or a mixture of two or more solvents. The boiling point is a value measured by a Japanese pharmacy method.

  The organic solvent (A) and the organic solvent (B) are not particularly limited as long as the condensation reaction product of the polysiloxane compound and the silica particles dissolves, but alcohol, polyhydric alcohol derivative, ketone, ester, ether, and carbonization are respectively used. Selection from hydrogen is preferable from the viewpoint that the pot life of the condensation reaction product is good.

  Preferable specific examples of the organic solvent (A) include alcohols such as butanol and methoxyethanol; polyhydric alcohol derivatives such as propylene glycol monomethoxy ether, ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol dimethyl ether. , Propylene glycol monomethyl ether, etc .; as ketones, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, etc .; as esters, butyl acetate, propyl propionate, etc .; as ethers, butyl ethyl ether, butyl propyl ether, and polyhydric alcohol derivatives As mentioned above, propylene glycol monomethoxy ether, ethylene glycol dimethyl ether Ethylene glycol diethyl ether, propylene glycol dimethyl ether and propylene glycol monomethyl ether and the like; hydrocarbon, toluene and the like; and the like.

  The boiling point of the organic solvent (A) is preferably 70 ° C. or higher, more preferably 80 ° C. or higher, from the viewpoint of the film formability of the coating film, and preferably 130 ° C. or lower, more preferably, from the viewpoint of trench embedding property. 125 ° C. or lower.

  Preferable specific examples of the organic solvent (B) include alcohols such as pentanol, hexanol, octanol, ethoxyethanol, and ethylene glycol; polyhydric alcohol derivatives such as propylene glycol monoethoxy ether, propylene glycol diethyl ether, and ethylene glycol isopropyl ether. , Methoxymethoxyethanol, ethylene glycol diacetate, etc .; as ketones, isoamyl ketone, ethylhexyl ketone, cyclohexanone, gamma butyrolactone, etc .; as esters, pentyl acetate, hexyl acetate, butyl propionate, pentyl propionate, hexyl propionate , Propylene glycol monomethyl ether acetate, ethyl lactate, etc .; as ether, dibutyl ether, aniso Le, as well as the above-described polyhydric alcohol derivatives, propylene glycol monomethyl ethoxy ether, propylene glycol diethyl ether, and the like; hydrocarbon, xylene; and the like.

  The boiling point of the organic solvent (B) is preferably 130 ° C. or more, more preferably 140 ° C. or more from the viewpoint of trench embedding properties, and preferably 220 ° C. or less, more preferably from the viewpoint of film formability of the coating film. It is 210 degrees C or less.

  In the present embodiment, the organic solvents (A) and (B) may be in a predetermined organic solvent mixing ratio when the trench filling condensation reaction solution is applied. For example, after synthesizing a condensation reaction product of a polysiloxane compound and silica particles, an organic solvent can be added to the condensation reaction product to adjust the mixing ratio.

  Another aspect of the present invention is a trench embedding process including the step of applying the above-described condensation reaction product solution according to the present invention to a substrate having a trench, and the step of firing the substrate coated with the condensation reaction product solution. A method for manufacturing a membrane is provided.

  In a preferred embodiment, the application is performed by a spin coating method. The above-described condensation reaction solution for filling the trench can be applied to the substrate having the trench by a usual method. As a coating method, for example, any known coating method such as spin coating, spray coating, or roll coating can be used. In particular, in the case of a semiconductor device, the spin coating method is preferable because the film thickness uniformity of the coating film is good. The application conditions may be appropriately selected according to the desired film thickness of the trench filling film to which the present invention is applied. When applying by a spin coating method, it may be applied at a single rotation speed or a combination of multiple rotation speeds, but at least the rotation speed at the first stage is 50 rpm or more and 3000 rpm or less. Is preferred. This is because the coating liquid can be spread uniformly over the entire surface of the silicon substrate at 50 rpm or higher, and the organic solvent (A) is evaporated moderately at 3000 rpm or lower, so that the effect of improving trench embedding properties appears strongly. . Further, the number of times of applying the trench filling condensate reaction solution may be one or more times, but it is more preferable to apply the solution once because the film-forming property is improved and the manufacturing cost is improved.

Next, the substrate coated with the condensation reaction product solution is baked. However, it is preferable from the viewpoint of transporting the coating film that the pre-curing step is performed after the coating solution is coated on the substrate and before firing. This preliminary curing is performed by a hot plate, an oven, a furnace, or the like. Thereafter, a silicon oxide can be obtained by heating and baking a film obtained by pre-curing. This pre-curing temperature is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, and still more preferably 70 ° C. or higher, from the viewpoint of trench embedding properties. More preferably, it is 280 degrees C or less, More preferably, it is 260 degrees C or less. Further, as an atmosphere at the time of preliminary curing, an oxidizing atmosphere such as air, oxygen or water vapor can be used in addition to an inert atmosphere such as N ₂ and Ar.

As a baking method, general heating means such as a hot plate, an oven, and a furnace can be applied. The heat treatment temperature is preferably 100 ° C to 1,200 ° C, more preferably 200 ° C to 1,100 ° C, and further preferably 300 ° C to 1000 ° C. The heat treatment temperature within the above range is preferable from the viewpoint of high film density after firing and good film quality. As an atmosphere at the time of heating and baking, in addition to an inert atmosphere such as N ₂ or Ar, an oxidizing atmosphere such as air, oxygen, or water vapor can also be used. There is no restriction | limiting in particular in the pressure at the time of a heat-firing process, It can implement by any pressure under pressure, a normal pressure, pressure reduction, or a vacuum.

  Hereinafter, embodiments of the present invention will be described in detail with reference to Examples and Comparative Examples. The present invention is not limited to these.

Production Example 1 of Solution of Condensation Reaction Product of Polysiloxane Compound and Silica Particles-1
In a 300 mL eggplant flask, 31.20 g of tetraethoxysilane and 61.89 g of ethanol were added and stirred, and then a mixed aqueous solution of 4.59 g of 0.7 mass% nitric acid aqueous solution and 6.24 g of water was added dropwise at room temperature. After completion of dropping, the mixture was heated and stirred at 50 ° C. for 1 hour. After heating and stirring, a mixed solution of PL-06 (water dispersion silica particles having an average primary particle diameter of 6 nm and a concentration of 6.3% by mass, manufactured by Fuso Chemical Industries) and 58.14 g of ethanol was added dropwise at room temperature. After completion of dropping, the mixture was heated and stirred at 50 ° C. for 1 hour. Thereafter, 150 g of propylene glycol monomethyl ether (boiling point: 120 ° C.) was added, the temperature of the oil bath was raised, and ethanol, water, and nitric acid were distilled off from the distillation line to obtain a propylene glycol monomethyl ether solution of the condensation reaction product. . By concentrating the propylene glycol monomethyl ether solution of the condensation reaction product, 85.70 g of a condensation reaction product solution having a concentration of 15% by mass in terms of SiO ₂ was obtained.

Production Example 2 of Solution of Condensation Reaction Product of Polysiloxane Compound and Silica Particles-2
In a 300 mL eggplant flask, 31.20 g of tetraethoxysilane and 61.89 g of ethanol were added and stirred, and then a mixed aqueous solution of a 0.7 mass% nitric acid aqueous solution 4.59 g and water 6.24 g was added dropwise at room temperature. After completion of dropping, the mixture was heated and stirred at 50 ° C. for 1 hour. After heating and stirring, a mixed solution of PL-06 (water dispersion silica particles having an average primary particle diameter of 6 nm and a concentration of 6.3% by mass, manufactured by Fuso Chemical Industries) and 58.14 g of ethanol was added dropwise at room temperature. After completion of dropping, the mixture was heated and stirred at 50 ° C. for 1 hour. Thereafter, 150 g of ethylene glycol (boiling point: 191 ° C.) was added, the temperature of the oil bath was raised, ethanol, water, and nitric acid were distilled off from the distillation line to obtain an ethylene glycol solution of the condensation reaction product. By concentrating the ethylene glycol solution of the condensation reaction product, 85.70 g of a condensation reaction product solution having a concentration of 15% by mass in terms of SiO ₂ was obtained.

(Evaluation of trench fillability)
What prepared the said condensation-reaction thing on each condition of the following Example and a comparative example was used for spin coater (the Tokyo Electron make, clean track Mk-8) on Si substrate which has a trench of opening width 15nm and depth 250nm. Then, the coating film was formed by rotating at 1600 rpm for 30 seconds. After this coating film was pre-cured stepwise in this order on a hot plate at 50 ° C., 100 ° C., and 150 ° C., argon was added to the furnace at 25 L / min using an electric tubular furnace (manufactured by Irie Shokai, MIK-5). Then, the temperature was raised from 23 ° C. to 930 ° C. at a rate of temperature rise of 20 ° C./min, and kept at 930 ° C. for 30 minutes to carry out the firing step. The obtained fired substrate is cleaved in a direction perpendicular to the longitudinal direction of the trench, and a trench 100 is randomly selected from a sample piece at a magnification of 80,000 times using a scanning electron microscope (manufactured by Hitachi, S-4800). When the book is observed, all the trenches are filled with the fired product of the condensation reaction product for filling the trench, and voids such as grooves, holes and cracks are not observed. The case where such a void was observed was regarded as poor embeddability.

Example 1
A coating solution prepared by adding gamma butyrolactone (boiling point: 204 ° C.) to the condensation reaction product synthesized in Production Example 1 so that the amount of gamma butyrolactone is 1% by mass with respect to the whole organic solvent in the condensation reaction solution. Was evaluated based on the above-described trench embedding evaluation method. As a result, voids such as grooves, holes and cracks were not observed, and the embeddability was good.

Example 2
For the coating solution prepared by adding gamma butyrolactone to the condensation reaction product synthesized in Production Example-1 so that the amount of gamma butyrolactone is 40% by mass with respect to the total organic solvent in the condensation reaction solution, Evaluation was performed based on the evaluation method. As a result, voids such as grooves, holes and cracks were not observed, and the embeddability was good.

Example 3
Coating solution prepared by adding ethyl lactate (boiling point: 154 ° C.) to the condensation reaction product synthesized in Production Example-1 so that the ethyl lactate is 10% by mass with respect to the total organic solvent in the condensation reaction solution. Was evaluated based on the above-described trench embedding evaluation method. As a result, voids such as grooves, holes and cracks were not observed, and the embeddability was good.

Comparative Example 1
The condensation reaction product synthesized in Production Example-1 was used as it was as a coating solution, and evaluation was performed based on the above trench embedding evaluation method. As a result, voids such as grooves, holes, cracks and the like were observed, so that the embedding property was poor.

Comparative Example 2
The condensation reaction product synthesized in Production Example-2 was used as it was as a coating solution, and evaluation was performed based on the above-described trench embedding evaluation method. As a result, voids such as grooves, holes, cracks and the like were observed, so that the embedding property was poor.

Comparative Example 3
With respect to the coating solution prepared by adding gamma butyrolactone to the condensation reaction product synthesized in Production Example-1 so that the amount of gamma butyrolactone is 60% by mass with respect to the total organic solvent in the condensation reaction solution, Evaluation was performed based on the evaluation method. As a result, voids such as grooves, holes, cracks and the like were observed, so that the embedding property was poor.

Comparative Example 4
With respect to the coating solution prepared by adding gamma butyrolactone to the condensation reaction product synthesized in Production Example-2 so that the amount of gamma butyrolactone is 10% by mass with respect to the total organic solvent in the condensation reaction solution, Evaluation was performed based on the evaluation method. As a result, voids such as grooves, holes, cracks and the like were observed, so that the embedding property was poor.

  The present invention is suitably applied to an insulating protective film in a trench formed in a semiconductor element.

Claims (3)

A condensation reaction solution for trench filling, comprising a condensation reaction product of a polysiloxane compound and silica particles, and an organic solvent,
The polysiloxane compound has the following general formula (2):
SiX ² ₄ (2)
{Wherein X ² represents a halogen atom, an alkoxy group having 1 to 6 carbon atoms or an acetoxy group, and a plurality of X ² may be the same or different. }
Derived from the tetrafunctional silane compound represented by
The organic solvent has an organic solvent (A) having a boiling point of less than 130 ° C. and a boiling point of 154 ° C. or more and 220 ° C. or less with respect to a total amount of the organic solvent of 100% by mass. the solvent (B) of 50 mass% 1 mass% or more look-containing,
A condensation reaction product solution for trench filling, wherein the organic solvent (B) is at least one selected from the group consisting of ketones and esters . The condensation reaction solution for trench embedding according to claim 1 , wherein the organic solvent (A) is at least one selected from the group consisting of alcohol, polyhydric alcohol derivative, ketone, ester, ether, and hydrocarbon. Applying the trench filling condensate reaction solution according to claim 1 or 2 to a substrate having a trench by a spin coating method;
And a step of baking the substrate coated with the condensation reaction product solution.